A young boy receives medical treatment for a gunshot wound in Baghouz, Syria. Civilians fleeing fighting have increased during the final operation to oust ISIS. Picture: Getty ImagesSource:Getty Images

Mr Trump at around 1600 GMT on Friday said announcements over “the eradication of the caliphate” would be made “over the next 24 hours”.

On Saturday, US-led coalition spokesman Colonel Sean Ryan acknowledged that the timeline had slipped because of the presence of civilians inside.

“There has been lapses as we continue to see hundreds of civilians still attempting to flee to safety,” he said.

Men who have fled fighting in Baghouz wait in the desert after being screened by members of the Syrian Democratic Forces (SDF). Picture: Chris McGrath/Getty ImagesSource:Getty Images

‘Hunt down’ ISIS remnants

Beyond Baghouz, ISIS still has thousands of fighters and sleeper cells scattered across several countries.

In Syria, it retains a presence in the vast Badia desert, and has claimed deadly attacks in SDF-held territory.

The US Department of Defence has warned that without sustained counter-terrorism pressure, IS could resurge within months.

US Vice President Mike Pence vowed on Saturday at a security conference in the German city of Munich that Washington would continue to fight ISIS remnants even after a military pullout.

German Chancellor Angela Merkel (R) warned US vice president Mike Pence that a US pullout will boost the role of Russia and Iran in Syria. Picture: Alexandra Beier/Getty ImagesSource:Getty Images

“The United States will continue to work with all our allies to hunt down the remnants of ISIS wherever and whenever they rear their ugly heads,” Mr Pence said.

German Chancellor Angela Merkel warned in Munich that a US pullout risks allowing regimen allies Russia and Iran to boost their role in Syria.

A US withdrawal risks leaving Syria’s Kurds exposed to a long-threatened attack by neighbouring Turkey, who views Kurdish fighters as “terrorists”.

To prevent this, they have scrambled to seek a new ally in the Damascus government after spending most of Syria’s civil war working towards self-rule.

Eight years into a war that has killed more than 360,000 people, President Bashar al-Assad’s government controls nearly two-thirds of the country.